Air gaging mechanism for centerless grinders



M 4, 1956 w. A. BOYD, JP 2,

AIR GAGING MECHANISM FOR CENTERLESS GRINDERS 7 Filed Feb. 10, 1954 2 Sheets-Sheet 1 Q Rm 1W 4, 1956 w. A. BOYD, JR AIR GAGING MECHANISM FOR CENTERLESS GRINDERS 2 Sheets-Sheet 2 Filed Feb. 10, 1954 United States Patent AIR GAGING MECHANISM FOR CENTERLESS GRINDERS Walter A. Boyd, Jr., Woodstock, Vt., assignor to Bryant Chucking Grinder Company, Springfield, Vt., a corporation of Vermont Application February 10, 1954, Serial No. 409,313

2 Claims. (Cl. 51-48) This invention relates to internal grinding machines and has for an object to provide for gaging the internal diameter of work by the use of an air gage, which may be arranged as a control element of an automatic grinding machine as shown and claimed in the Bryant et a1. Patent No. 2,585,533, granted February 12, 1950, but applied to a machine of the centerless grinding type.

This invention may be embodied in a centerless grinding machine wherein the work piece is held concentric with the spindle axis as by the well known use of skewed supporting rolls, or as disclosed and claimed in the application for patent of Edward L. Dix, Serial No. 366,217,

filed July 6, 1953, for Centerless Grinding Machine pursuant to which application Patent No. 2,723,499 was granted November 15, 1955.

It may also be embodied in a centerless grinding machine wherein the work piece is held eccentric to the work spindle as disclosed and claimed, for example, in the Arms Patent No. 2,635,395, granted April 21, 1953, for Machine for Grinding Internal Surfaces Concentric with External Surfaces.

It may also be combined with mechanism for directing 1 j coolant to the surfacesbeing ground.

For a more complete understanding of this invention, reference may be had to the accompanying drawings in which Figure 1 is a view partly in side elevation and partly broken away and in section of a grinding machine work head of a centerless grinding machine embodying the invention.

Figure 2 is a perspective view ot a gage supporting sleeve.

Figure 3 is a perspective view of an air discharge head.

Figure 4 is a detail sectional View to a larger scale on line 4-4 of Figure 1 and showing the work piece supported eccentrically to the driving spindle, and using the air discharge head of Figure 3.

Figure 5 is a view similar to a portion of Figure 4 but to a larger scale.

Figure 6 is a detail sectional view to a larger scale on line 6--6 of Figure 1.

Figure 7 is a detail sectional view on line 7-7 of Figure 6.

Referring first to Figure 1 of the drawings, at 1 is indicated a hollow work spindle suitably journaled at 2 in a grinding head 3. Suitable means for rotating this spindle are employed, and as shown, a pulley 4 keyed thereto and held in position by a nut 5 threaded on the end portion of the spindle is illustrated for this purpose.

The opposite end portion of the spindle is shown as provided with a standard nose 9 which carries an adapter plate 6 to which is secured a hollow driver 7. This driver 7 has an internal bore 8 preferably of a size slightly larger than the interior of the finished work piece which is to be ground by the machine. Such a work piece is shown at 10 and as shown it is an internal ball raceway member. This raceway member may be supported for rotation centered from its externally finished face by the rotation 2,772,519 Patented Dec. 4, 1956 of the spindle by any suitable means, a pair of angularly spaced shoes 11 each carrying a ball 12 engaging in the raceway groove 13 being shown for the purpose (see Figure 4).

The work piece to be ground is clamped against the outer end of the driver 7, or against a clamping ring 14 secured thereto, as by an annular clamping member 15 which may be pressed the-reagainst. This annular clamping member 15 may be of the type shown in the Arms et al. Patent No. 2,635,395, being arranged con-centric with the spindle while the work piece is held by the shoes 11 slightly eccentric thereto, or it may be mounted slightly eccentric to the spindle axis while the work piece is held concentric thereto as disclosed and claimed in the Dix patent hereinbefore mentioned. A grinding wheel 16 is arranged to engage the inner face of the Work piece 10 to efiect the grinding action, this grinding wheel being reciprocated during the grinding operation so as to pass entirely through the work piece. Its lateral pressure on the work piece is in direction to aid in holding this work piece against the shoes 11.

A non-rotary air dis-charge gaging head 20, shown in Figures 3 and 4, may be employed. It includes a hollow cylindrical shank member 21 which may be mounted in a pilot collar 22 secured to the outer end of a tube 25. This tube 25 extends through the spindle 1, but is held from rotation therewith, though it is given an axial movement therethrough. It is suitably supported within the rotary spindle 1 in bearings as at 27.

Where the work piece is held concentric to the spindle axis, as is well known in the prior art, or as is shown in the Dix patent to which reference has been made, the outer portion of the collar 22 will have its inner bore concentric to its rear end portion, but where the work piece is supported eecentrically, the outer bore which receives the portion 21 of the air discharge nozzle is arranged with corresponding eccentricity (see Figures 2, and 4 to 7, inclusive), and the collar 22 is fixed in proper angular position on the tube 25 to position the non-rotating gage head concentric with the rotatable work piece as by means of a set screw 26 passing through a threaded hole 23 in the collar 22. The non-rotatable air discharge head is thus arranged concentric with the work piece whether or not this is concentric to or eccentric to the spindle by the selective use of a pair of such nozzles each being designed for one of these arrangements.

Compressed air is supplied to the interior of the discharge nozzle 20 as through a tube or pipe 30 which extends through the tube 25. This tube 30 may well be of flexible material so that it may conform readily to either concentric or eccentric relation at its forward end to the tube 25 which is always concentric with the spindle 1. It may, for example, be formed of suitable plastic. The air tube 30 is connected at the: rear end of the tube 25 to a suitable air supply pipe 31 which may be arranged in connection with the remainder of the air gage mechanism in the manner shown in the Bryant et a1. Patent No. 2,585,533 which has been heretofore mentioned.

The non-rotatable mechanism including the tube 25 and the air discharge head and its related mechanism, is arranged for reciprocation in time with the reciprocation of the grinding wheel 16. As shown in Figure 1 such mechanism comprises a lever 40 fulcrumed at a fixed point 41 and having a yoke portion at 42, which engages in a transverse groove 43 in a reciprocating head 44 fixed to the rear end of the tube 25. Intermediate to its ends, this tube may be provided with a suitable T fitting 45 through a branch 46 of which coolant may be supplied to the interior of the tube 25 and surrounding the tube 30, as through a pipe 47. The coolant may escape through the shank portion 21 of the air discharge head into the interior of the work piece. The lever 40 is normally pressed toward a position where the air discharge head is within the work piece by a spring 50 secured at one end to the lever 40 and at the other to a suitable fixed element '51, and when the interior of the work piece is of suificient size to permit the entry of the discharge head therein, this head may be pushed thereinto by the spring 50 whenever the grinding wheel is sufliciently retracted to avoid contact therewith.

One end of the lever 40 is provided with a cam follower roll 55 against which bears a cylindrical abutment 56 carried by a lever 57 fulcrumed at a fixed point 58 and engaging at its opposite end in the groove of a spool member 60 secured to a reciprocable rod 61 mounted in a portion of the head 3. The grinding wheel 16 is carried by a Wheel head which is provided with a plunger portion 62 which may make contact with the end of the rod 61. As the Wheel head is caused totraverse the interior of the work piece, this plunger 62 is moved axially and when the wheel extends well within the work, it contacts with the rod 61 and moves it axially rocking the levers 57 and 40 to withdraw the air discharge head from the work so that the wheel cannot contact therewith.

On retraction of the grinding Wheel, the air discharge head is allowed to be moved by the spring 50 toward the work piece and when the interior of the work piece is sufiiciently large to permit entry, the air gage may enter the work and become eifective to gage its size.

It will be noted that the work piece and also the driver 7 against which it is clamped rotate, so that the effect of the relative motion between the rotating parts and the non-rotating air discharge head is produced at all times during the operation of the machine so that the swipe or boundary layer effect of gaging a rotating surface with a non-rotating air gaging element is taken into account in the air gage mechanism, regardless of whether the gaging head is within the work piece or within the driver. It will also be noted that whether or not the work piece is arranged concentric with the work spindle, the air discharge head is concentric with the work piece.

From the foregoing description of certain embodiments of this invention it should be evident to those skilled in the art that various changes and modifications may be made therein without departing from its spirit or scope.

I claim:

1. In combination, a rotary hollow spindle, means for supporting said spindle, a driver secured to one end of said spindle and having a bore concentric with said spindle of slightly larger diameter than the finished bore of a work piece to be held thereagainst, a non-rotatable first tube extending through and movable lengthwise of said spindle, means for supporting said tube, means for clamping a work piece against said driver to be rotated by rotation of said spindle, a pilot collar secured to the inner end of said tube and having a bore concentric with the work piece, an air gage nozzle held by said collar concentric with said work piece, a second tube within said first tube and leading to said nozzle for supplying air under pressure to said nozzle, said nozzle directing air between it and the wall of said bore when said nozzle is within said work piece and between it and said driver bore when said nozzle is within said driver bore, and means for reciprocating said non-rotatable tube and parts carried thereby to move said nozzle longitudinally within said driver bore and when the bore of said work piece is of sufiicient size into and out of the work piece, a rotary grinding wheel positioned to act upon the bore of said work piece, connections between said grinding wheel and first tube for moving said grinding wheel and first tube in timed relation to prevent contact between said nozzle and grinding wheel while permitting said nozzle to enter the work piece when said grinding wheel is in proper axial position and the hole in the work piece is of sufficient-size, and means for delivering coolant through said first tube and outwardly of said air tube past side nozzle into the work piece.

2. In combination, a rotary hollow spindle, means for supporting said spindle, a driver secured to one end of said spindle and having a bore concentric with said spindle of slightly larger size than the finished bore of a work piece to be held there against, means for clamping said work piece against said driver, a non-rotatable tube extending through and movable lengthwise of said spindle, means for supporting said tube, an air gage nozzle held by said tube concentric with the bore of said work piece, an air tube within said non-rotatable tube and leading to said nozzle for supply air under pressure to said nozzle, and means for delivering coolant between said tubes past said nozzle into the work piece.

References Cited in the file of this patent UNITED STATES PATENTS 1,770,148 Stevens July 8, 1930 2,109,524 Cramer Mar. 1, 1938 2,176,248 Cramer Oct. 17, 1939 2,502,862 Ljunggren Apr. 4, 1950 2,585,533 Bryant et al. Feb. 12, 1952 2,635,395 Arms et al. Apr. 21, 1953 2,723,499 Dix Nov. 15, 1955 

